Vibes - There is a TSB / SB on it
All, I have been following TDR forum for sometime as a non-member. The level of discussions on this forum are far and away more technical / information than most other diesel truck forums!
Anyway - I have followed WStoops saga - sorry about your truck. Mine had similar vibe 68 to 72, buzz in steering wheel

- an at 6000 miles I took it in. The dealer in Leesburg VA is excellent, and called DC Zone rep that day - no work was done. 10 days later the zone rep came and drove and verified vibe. He recommend to the dealer to use a just released Service Bulletin [ I did not get the number yet] that entails raising/ lowering the transfer case to change rear pinion angle.
After 2-3 attempts, the vibe in the 68-72 range is reduced / gone. I can't tell the difference from 50 mph to about 73 or so. What I do notice is that at 74 to about 77 there is a bit of "strumming" like a beat frequency recurring every 1 second or so. Especially noticeable when pulling 5000 lbs up 7% grade at WOT.
This was 1 week ago - so far the vibe has not recurred in the 68-72 range.
Next time the zone rep is in town, I have an appointment for him to ride with me and observe the 74-77 mph issue.
But all in all, Leesburg C/D has been an excellent dealer and these guys understand this problem, and want to help fix it. They did buy one truck back for same.
Luke
04. 5 - 2500 4x4 LWB, QC, 4:10, 6Speed, Cummins 600, stock tires, wheels no additions other than G/N hitch and step bars.